I almost lost the cap to my cassette toilet tank while emptying it. I know several people that have actually lost the cap in the drain at a dump station. They are hard to obtain from Thetford, but these are the perfect replacement! Exact fit. Hopefully I won't loose either of them!
I’ve been looking for several years for this particular part with no luck. So glad I found a place who has the parts I need, as it’s really hard to find stores that have pop up camper parts.